基于NI PXI起步意图对离合器结合过程影响分析

Influence Analysis of Clutch Engagement Process From the Under Different Starting Intention Based on NI PXI System

不同起步意图的油门开度和变化率差异较大,对离合器结合过程的冲击速度影响较大。针对离合器结合过程进行分析,建立整个过程的数学模型和动力学模型,建立影响车辆换挡品质的评价指标对离合器结合过程进行评价;基于Simulink建立离合器结合过程的分析模型;采用Matlab/RWT和NI-PXI系统建立整个离合器系统的实时仿真模型;分析不同算法和步长对实时仿真结果的影响,获取最优步长设计;分析缓起步、正常起步和急起步等三种不同的起步意图对离合器结合过程的影响规律。结果可知:步长e3的误差较大,而e4与e5的结果相差较小,e4与实际结果更为接近,应选择步长为e4进行实时分析;急起步阶段摩擦片冲击度最大值为7.2m/s,稍大于缓起步情况,但小于国际标准的10m/s满足要求;随着油门开度和油门变化率的逐渐增大,离合器结合角速度和结合时间都有所增大,结合过程产生的滑摩功也不断增多;分析结果为此类设计提供参考。

Throttle opening and rate of change with different starting intentions are quite different,which has a greater impact on the speed of the clutch engagement process.The clutch engagement process was analyzed,so the mathematical model and dy⁃namic model of the entire process was established.The evaluation index that affects the shift quality of the vehicle to evaluate the clutch coupling process was established.The analysis model of the clutch engagement process based on Simulink was built.Based on the above analysis,the real-time simulation model of the entire clutch system was established based on Matlab/RWT and NI-PXI system.The effects of different algorithms and step sizes on real-time simulation results were analyzed to obtain optimal step size design.The influence on the clutch engagement process of three different starting intentions was analyzed,such as slow start,normal start and rapid start.The results show that the error of step e3 is large,while the results between e4 and e5 are small dif⁃ference,and e4 is closer to the actual result.The step size of e4 should be selected for real-time analysis.The maximum value of the friction plate impact during the rapid start is 7.2 m/s,slightly larger than the slow start situation,but less than the interna⁃tional standard of 10m/s to meet the requirements.With the gradual increase of the throttle opening and the rate of change of the throttle,the clutch engagement angular velocity and engagement time have increased.The friction and friction work generated during the combination process has also increased.The analysis results provide a reference for such designs.